ORG.oclc.Telnet.socket
Class TelnetWrapper

java.lang.Object
  |
  +--ORG.oclc.Telnet.socket.TelnetWrapper

public class TelnetWrapper

extends Object

Wrapper for a Java Telnet call. To use, make a new TelnetWrapper() with the name or IP address of a host. Then, for most uses, the easiest way is to call setPrompt() with the expected prompt, then call login(), and a sequence of sendLine()'s until you get what you want done.

If you don't know the prompt ahead of time, you have to do a sequence of send() and wait() or receiveUntil() calls. send() sends a string across the telnet connection. Add a '\r' to the end if you want to complete a command. wait() waits for an exact string from the other side of the telnet connection, and returns nothing, receiveUntil() also waits for a string, but returns all the data that it received while waiting, including the string itself. Use this if you want the output from a command. Please note that the telnet connection will usually echo the sent command.

sendLine() is generally better, since it adds the '\r' automatically, waits for the prompt before returning, and returns all data received before the prompt, with the prompt itself cut off the end, and the sent command cut off the beginning. login() and sendLine() are implemented using send(), wait() and receiveUntil(). They can be freely mixed and matched.

Here is a simple example of the use of TelnetWrapper:

 // creates a new file in /tmp, lists the directory to prove it done
 {
   TelnetWrapper telnet = new TelnetWrapper("123.45.78.90");

   // setting the correct prompt ahead of time is very important 
   // if you want to use login and sendLine
   telnet.setPrompt("$ ");
   telnet.login("loginname", "password");

   // this is how you have to do it otherwise
   telnet.send("touch /tmp/TELNET_WRAPPER" + "\r");
   telnet.wait("$ ");

   // sendLine 1: adds the \r automatically, 2: waits for the prompt
   // before returning 3: returns what was printed from the command
   String ls = telnet.sendLine("ls /tmp");
   System.out.println(ls);

   // clean up
   telnet.disconnect();
 } 
 

See Also:

TelnetIO

Field Summary

boolean

debug Set to true for System.out.println debugging.

Constructor Summary

TelnetWrapper(String host)
Connects to the default telnet port on the given host.

TelnetWrapper(String host, int port)
Connects to a specific telnet port on the given host.

Method Summary

int	available() Returns bytes available to be read.
void	disconnect() Ends the telnet connection.
void	finalize() Ends the telnet connection.
void	login(String loginName, String password) Logs in as a particular user and password.
static void	main(String[] args) Telnet test driver.
String	receive() Returns a String from the telnet connection.
byte[]	receiveBytes() Returns a byte array.
String	receiveUntil(String token) Returns all data received up until a certain token.
String	receiveUntil(String token, long timeout) Returns all data received up until a certain token.
void	send(byte[] buf) Sends bytes over the telnet connection.
void	send(String s) Sends a String to the remote host.
String	sendLine(String command) Sends a line to the remote host, returns all data before the prompt.
static void	setDefaultPrompt(String prompt) Sets the default prompt used by all TelnetWrappers.
static void	setLogin(String login, String password) Sets the default login used by TelnetWrappers.
void	setPrompt(String prompt) Sets the expected prompt.
static void	unsetLogin() Turns off the default login of TelnetWrappers.
void	wait(String token) Skip any received data until the token appears.
void	wait(String token, long timeout) Wait for a String or a timeout.

Methods inherited from class java.lang.Object

clone, equals, getClass, hashCode, notify, notifyAll, toString, wait, wait, wait

Field Detail

debug

public boolean debug

Set to true for System.out.println debugging.

Constructor Detail

TelnetWrapper

public TelnetWrapper(String host)
              throws IOException

Connects to the default telnet port on the given host. If the defaultLogin and defaultPassword are non-null, attempts login.

TelnetWrapper

public TelnetWrapper(String host,
                     int port)
              throws IOException

Connects to a specific telnet port on the given host. If the defaultLogin and defaultPassword are non-null, attempts login.

Method Detail

wait

public void wait(String token)
          throws IOException

Skip any received data until the token appears. More efficient than receiveUntil, but liable to fail on large tokens that can be spread over several "send"s. In that case, consider using receiveUntil and ignoring the return value.

Parameters:

token - String to wait for

Throws:

IOException - on problems with the socket connection

See Also:

receiveUntil(java.lang.String)

wait

public void wait(String token,
                 long timeout)
          throws IOException,
                 TimedOutException

Wait for a String or a timeout. If time runs out, throws a TimedOutException. Sleeps in intervals of 100 milliseconds until either receiving the token or timeout.

More efficient than receiveUntil, but liable to fail on large tokens that can be spread over several "send"s. In that case, consider using receiveUntil and ignoring the return value.

Parameters:

token - String to wait for

timeout - time in milliseconds to wait (negative means wait forever)

Throws:

IOException - on problems with the socket connection

TimedOutException - if time runs out before token received

See Also:

receiveUntil(String, long)

available

public int available()
              throws IOException

Returns bytes available to be read. Since they haven't been negotiated over, this could be misleading...

receive

public String receive()
               throws IOException

Returns a String from the telnet connection. Blocks until one is available. No guarantees that the string is in any way complete. NOTE: uses Java 1.0.2 style String-bytes conversion.

receiveBytes

public byte[] receiveBytes()
                    throws IOException

Returns a byte array. Blocks until data is available.

receiveUntil

public String receiveUntil(String token)
                    throws IOException

Returns all data received up until a certain token.

Parameters:

token - String to wait for

Throws:

IOException - on problems with the socket connection

See Also:

wait(java.lang.String)

receiveUntil

public String receiveUntil(String token,
                           long timeout)
                    throws IOException,
                           TimedOutException

Returns all data received up until a certain token.

Parameters:

token - String to wait for

timeout - time in milliseconds to wait (negative means wait forever)

Throws:

IOException - on problems with the socket connection

TimedOutException - if time runs out before token received

See Also:

wait(String, long)

send

public void send(String s)
          throws IOException

Sends a String to the remote host. NOTE: uses Java 1.0.2 style String-bytes conversion.

Throws:

IOException - on problems with the socket connection

sendLine

public String sendLine(String command)
                throws IOException

Sends a line to the remote host, returns all data before the prompt. Since telnet seems to rely on carriage returns ('\r'), one will be appended to the sent string, if necessary.

Parameters:

command - command line to send

Returns:

whatever data the command produced before the prompt.

See Also:

setPrompt(java.lang.String)

send

public void send(byte[] buf)
          throws IOException

Sends bytes over the telnet connection.

login

public void login(String loginName,
                  String password)
           throws IOException

Logs in as a particular user and password. Returns after receiving prompt.

setPrompt

public void setPrompt(String prompt)

Sets the expected prompt. If this function is not explicitly called, the default prompt is used.

See Also:

setDefaultPrompt(java.lang.String)

setDefaultPrompt

public static void setDefaultPrompt(String prompt)

Sets the default prompt used by all TelnetWrappers. This can be specifically overridden for a specific instance. The default prompt starts out as "$ " until this function is called.

See Also:

setPrompt(java.lang.String)

setLogin

public static void setLogin(String login,
                            String password)

Sets the default login used by TelnetWrappers. If this method is called with non-null login and password, all TelnetWrappers will attempt to login when first created.

Parameters:

login - login name to use

password - password to use

See Also:

login(java.lang.String, java.lang.String), unsetLogin()

unsetLogin

public static void unsetLogin()

Turns off the default login of TelnetWrappers. After this method is called, TelnetWrappers will not login until that method is explicitly called.

See Also:

setLogin(java.lang.String, java.lang.String), login(java.lang.String, java.lang.String)

disconnect

public void disconnect()
                throws IOException

Ends the telnet connection.

finalize

public void finalize()

Ends the telnet connection.

Overrides:

finalize in class Object

main

public static void main(String[] args)
                 throws IOException

Telnet test driver. Modeled after the IOtest.java example in the Telnet Applet. Logs in to "host", creates a timestamped file in /tmp, lists the /tmp directory to System.out, disconnects. Shows off several TelnetWrapper methods.

Parameters:

args - host login password prompt